On the Promoted Listings, are the Suggested Ad Rates only for the promoted part, separate from sales fees?

You do not have to be the least expensive when advertising. Quite often we have been the most but still make good sales.

However, you do have to make sure you cover your ad cost in your pricing. Also, start at 4.5% and see if you make sales. If you do, optimize the listing. If you do not, raise it to 6%.

Once you continue to make sales, test the waters by dropping the percentage a bit, etc.